KYIV -- Thousands of protesters are gathered in the center of Kyiv demanding that President Viktor Yanukovych veto a new tax bill they say is unfair, RFE/RL's Ukrainian Service reports.

At its peak there were an estimated 4,000 demonstrators on the city's main square who blocked the main boulevard, Kreshchatyk. By nightfall, a few thousand remained and pledged to spend the night on the square.

A protester told RFE/RL that a deadline of 6 p.m. was set for Yanukovych to veto the tax bill, which was passed by parliament on November 18. Organizers threatened to establish a committee calling for Yanukovych's impeachment if he does not veto the bill and they demanded the dismissal of Prime Minister Mykola Azarov and other authors of the tax code.

Presidential administration head Serhiy Lyovochkin said today in Brussels, where Yanukovych is attending an EU-Ukraine summit, that Yanukovych will evaluate the protesters' demands but cannot rule on the legislation because it has not yet been submitted to his office.

Yanukovych said in Brussels that he would meet with the organizers of the protests.

"I understand their demands very well," he said, "but their demands will never be completely met. We will be gradually moving from the simplified [tax] system to a system of taxation that reflects the growth of the real economy and brings the Ukrainian economy out of the shadows."

He added that the government will create incentives for businesses, such as "exempting small and medium-sized businesses, for a certain period of time, from the corporate profit tax."

Speaking today in Kyiv at the opening of a Ukrainian-Belgian economic forum, Azarov described the tax bill as "the most liberal in Europe."

A Kyiv court today banned public meetings in Kyiv until November 25. It is unclear whether the police will try to enforce the court decision. The court ruling came after a complaint filed by Kyiv city administration head Oleksandr Popov, who was appointed by Yanukovych last week.

Protest organizers banned alcohol at the gathering and have asked musicians to come to support their cause.

Earlier today, protesters said police had intercepted 140 buses in which owners of small businesses were traveling to Kyiv from other regions to participate in the protest. The authorities denied those reports.

Protests against the new tax code are taking place in several other Ukrainian cities.